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Student Research Spotlight - Elizabeth Davidson-Lowe

Posted: August 4, 2017

This is the 13th, and final, of the short news articles written by students, during the professional development class, about each other's research.

Living with fungus makes plants hormonal
by Angela Coco

Hormones. They influence our growth, feelings, fertility, and immunity. What do you think it would be like if another organism living inside you altered which of your hormones actively trigger? It may sound like a science fiction movie, but this life is a reality for plants.

Elizabeth Davidson-Lowe, a first-year entomology PhD candidate working under Jared Ali at Pennsylvania State University, wants to understand how organisms living in plant roots, mycorrhizal fungi (AMF), affect defenses of their partner by influencing plant hormones. “We often think of plants as bystanders, but they’re actually responding and interacting dynamically with other organisms,” she says. “Their [plants’] responses to each organism and situation can be very specific.”

AMF and plants have been interacting for hundreds of millions of years by exchanging nutrients and sharing space. Even more intimate, AMF affects how plants defend themselves against herbivories by influencing their hormone balance. When plants die or are removed, AMF fungal spores remain in the soil and wait for a new partner. Because some plant are selective about partners, they promote specific AMF communities in the soil. Additionally, hormone-triggered defenses vary among plant species, so AMF interactions with partners also vary. Therefore, farmer’s cover crops, plants in resting fields that help manage for soil erosion and other attributes, may influence how later planted cash crops, plants grown for market, defend themselves.

Plants use hormones to trigger different defenses to match the attacker, whether it be a leaf-muncher, a juice sucker, or a root chewer. Elizabeth wants to find out how AMF left in the soil from various cover crops affects the defense performance of different cash crops. Fungus A, for example, may trigger tomatoes to be ready for leaf eaters, but suppress its ability to protect roots. However, Fungus A’s effect on the leafy green Kale is opposite, which puts the crops’s marketability at risk. Therefore, the farmer should avoid planting cover crops that promote Fungus A where he plans to plant Kale.

Elizabeth’s research is part of a legacy of crop investigation by scientists at Penn State. From ecosystem services to soil quality, the story of crops and how they interact with the environment is gradually being revealed.